Enzyme granulation process

ABSTRACT

A process for producing granular product containing enzyme and builder salt, such as sodium tripolyphosphate, which comprises granulating an enzyme preparation and hydratable builder salt in the presence of ice particles at temperatures below about 30*C. to produce a granule wherein the hydratable builder salt is substantially completely hydrated and thermal degradation of the enzyme is minimized.

United States Patent [191 Natali et al.

EZXMEEMIYEMIIQ! OCE Inventors: Remigio Natali; Guiseppe Giombini,

both of Rome, Italy Assignee: Colgate-Palmolive Company, New

York, NY.

Filed: Mar. 28, 1972 Appl. No.: 238,991

Related U.S. Application Data Continuation of Ser. No. 38,560, May 18, I970, abandoned.

US. Cl 252/135, 23/3I3, 252/89, 252/99, 252/132, 252/525, 252/527,

252/DIG I2 Int. Cl...... Clld 3/06, Cl Id 7/42, Cl 1d II/OO Field of Search .l 252/89, 132, 135, 252/DIG. 12; 23/313 References Cited UNITED STATES PATENTS 6/1969 Roald et al. 252/135 1 Oct. 9, 1973 3,046,092 7/1962 Montague 23/l06 FOREIGN PATENTS OR APPLICATIONS 1,056,408 1/1967 Great Britain 252/135 Primary Examiner-Leon D. Rosdol Assistant Examiner-Dennis L. Albrecht Attorney-H. S. Sylvester et al.

3 Claims, N0 Drawings ENZYME GRANULATION PROCESS This is a continuation, of application Ser. No. 38,560 filed May 18, 1970 now abandoned.

This invention relates to a method of making a granular free-flowing, non-dusting, enzyme-containing composition having high enzyme activity and the method of using the composition in manufacturing enzymecontaining detergent products.

Powdered enzymes have been employed in presoak and washing detergent compositions since they are particularly effective against various common stains which are fixed to textiles and laundry. in particular, proteolytic enzymes, which possess the ability to digest and degrade protein matter, are effective in removing from textiles and laundry protein stains such as blood, sweat, milk, cocoa, gravy and other sauces, and the like. This digestion or degradation of protein matter facilitates removal of dirt by the detergent. Amylases and lipases are also useful in detergent cleaning.

However, the use of powdered enzymes in such compositions has resulted in certain problems including the presence of an excessive amount of dust. Some individuals experience allergic reactions to the enzyme dust. Furthermore, detergent compositions containing enzymes have been subject to discoloration, formation of undersirable odor and caking. Finally, the enzyme was subject to thermal degradation during the prior art agglomeration step because temperatures above 35C. were encountered whenever the hydratable salt was substantially completely hydrated.

To obviate or minimize the dust problem, it has been suggested to granulate various compounds which are common builder salts in their hydratable form with enzymes. Generally, this is done by contacting enzyme with an anhydrous or partially hydrated salt and adding water in an amount sufficient to partially hydrate the salt. However, such product still tends to exhibit high dust levels. Further, such water granulation results in higher granulation temperatures and local overheating in the granulation mixture with a consequent adverse effect on enzyme activity.

it is an object of the invention to provide a stable, non-dusting, free-flowing granulate composition wherein thermal degradation of the enzyme component is minimized. A further object of the invention is the production of a substantially non-dusty enzyme containing laundry detergent. Other objects will be apparent from the following description.

The described process minimizes the thermal degradation of enzymes during the granulation step and produces a substantially non-dusty product. By using particulate ice as the granulating agent for the enzyme and hydratable salt instead of liquid water, a portion of the heat of hydration is absorbed by the ice as it changes from the solid to the liquid state. Thus, only a portion of the heat produced during the exothermic hydration reaction is available to increase the temperature of the resultant product. Accordingly, high granulation temperatures and local overheating during the granulation step can be avoided, thereby minimizing thermal degradation of the heat sensitive enzyme so as to maintain high enzyme activity.

An important characteristic of the described process is the step of using ice particles to granulate the mixture of enzyme and hydratable builder salt. By using particulate ice as the granulating agent, the temperature of the granulation step is maintained below about 30C.

and thermal degradation of the enzyme material is minimized; whereas, in the prior art processes high temperatures cannot be avoided because the heat transfer of the granulation solids is too low to effectively transfer the heat of hydration of the hydratable salt from the granulation solids to a cooling medium. In addition, the described process also produces a product having lower dusting tendencies.

In accordance with certain of its aspects, this invention relates to a process for producing a granular enzyme product comprising granulating particulate enzyme with particulate hydratable builder salt in the presence of ice particles. The amount of ice which is added to granulate the enzyme-hydratable salt mixture must be effective to bind the enzyme to the salt and substantially eliminate enzyme dust while maintaining granulating temperatures below about 30C. The specific amount of ice used is variable and depends upon the relative proportions of enzyme and hydratable salts as well as the degree of hydration of the builder salts when partially hydrated builder salts are used. Generally, the amount of ice used will be sufficient to produce a hydrated salt containing about percent to about percent of the calculated weight of water' in a stable hydrate of the hydratable salt. For example, when the hydratable salt is anhydrous sodium tripolyphosphate, 0.294 parts by weight of ice are required for each part by weight of anhydrous tripolyphosphate to produce the calculated, stable sodium tripolyphosphate hexahydrate. While water in excess of the calculated amount of water in the stable hydrate may be present, the excess water present is necessarily limited by the requirement that a substantially dry, free-flowing product be produced. Accordingly, the amount of water must be integrated with the aforementioned variables to achieve the desired product.

The ice particles which are employed as the granulating agent generally have a particle size of about 0.1 mm to 10.0 mm and, preferably, a size of 0.5 mm to 5.0 mm. Ice particles of the foregoing sizes exhibit sufficient surface area to insure a substantially homogeneous hydration reaction and, at the same time, are large enough to provide a sufficient reservoir of ice during the mixing period for absorption of a portion of the heat of hydration. Thus, the reduced particle size of the ice is essential to insure a substantially homogeneous and controlled hydration and under conditions wherein temperatures may be maintained below about 30C., preferably within the range of about 20C. to 28C.

The mixing period during the granulation step is variable and must be integrated with the proportions of the hydratable salt and the enzyme preparation, the degree of hydration of the hydratable salt, the proportion and particle size of the ice, and the degree of mixing. Generally, a mixing period of about 2 to 10 minutes, preferably 3 to 5 minutes, is required to completely melt the ice and substantially homogeneously disperse the melted ice throughout the hydratable salt-enzyme mixture so as to produce a substantially dry, non-dusty, enzyme-containing granule having the desired particle size.

The process of the invention may be carried out by premixing the enzyme preparation and hydratable salt in a powder mixer and granulating the premix in a granulating mixer with agitation or by simultaneously adding enzyme preparation, hydratable salt, and ice parti-,

3 cle s to the granulating mixer. The granulating mixer may be the well-known Hobart mixer (whose mixing blade rotates about the blade axis and also moves in a circular path about the axis of the mixing vessel and close to the cylindrical internal wall of the mixing vessel) which has given smaller beads than the use of a conventional Day mixer (whose helical mixing blade also moves in a circular path about the axis of the mixing vessel and close to its cylindrical internal wall, but does not rotate about the blade axis). Another granulating mixer which may be used is the Patterson and Kelly Twin Shell Blender (whose mixing action is achieved by rotating the V-shaped vessel around a horizontal axis to obtain a dispersion of the particulate ice throughout the moving mixture of enzyme and hydratable inorganic salt). Other suitable granulating mixers are the granulating pans traditionally used by the pharmaceutical industry and the granulating drums used in the preparation of granular fertilizers.

Preferably, the process is carried out in such fashion as to produce beads or granules which pass through a mesh screen (screen opening 2 mm), more preferably through a 20 mesh screen (screen opening 0.84 mm), and are retained on an 80 mesh screen (screen opening 0.177 mm); the beads or granules within that size. range being more preferably a major proportion (and being most preferably at least about 70 percent, e.g., about 70-85 percent of the total weight of the product). All screen sizes used herein are U.S. Standard.

1n the preferred form of the invention the enzyme comprises a proteolytic enzyme which is active upon protein matter and catalyzes digestion or degradation of such matter when present as in linen or fabric stain in a hydrolysis reaction. Generally, the enzymes are effective in a pH range of about 4-12, and are effective even at moderately high use temperatures. They are also effective at ambient temperature and temperatures above about 10 C. Particular examples of proteolytic enzymes which may be used in the instant invention include pepsin, trypsin, chymotrypsin, papain, bromelin, colleginase,'keratinase, carboxylase, amino peptidase, elastase, subtilisin and aspergillopepidase A and 13. Preferred enzymes are subtilisin enzymes manufactured and cultured from special strains of spore forming bacteria, particularly bacillus subtilis.

Proteolytic enzymes such as Alcalase, Maxatase, Protease AP, Protease ATP 40, Protease ATP 120, Protease L-252 and Protease L-423 are among those enzymes derived from strains of spore foaming bacillus, such as bacillus subtillis.

Different proteolytic enzymes have different degrees of effectiveness in aiding in the removal of stains from textiles and linen. Particularly preferred as stain removing enzymes are subtilisin enzymes.

Metalloproteases which contain divalent ions such as calcium, magnesium or zinc bound to their protein chains are also of interest.

The enzyme preparations are generally extremely fine powders. In a typical powdered enzyme preparation the particle diameter generally ranges from 0.01 mm to 0.15 mm, e.g. about 0.1 mm, and as much as 75 percent of the material may pass through a 100 mesh (U.S. Standard) sieve. On the other hand the spray dried granules are usually of very much larger particle size, with the major portion of the granules being from about 0.2 to 2.0 mm in diameter.

The enzyme preparations are generally diluted with inorganic salts, e.g., alkali metal and alkaline earth metal salts. Typically the enzyme comprises from 1 to 80 percent by weight of the enzyme preparation. For example, a typical Alcalase enzyme material analyzes (by weight) 6.5 percent enzyme, 4 percent water, percent sodium chloride, 15.5 percent sodium sulfate, 3.5 percent calcium sulfate, and 0.5 percent organic impurities. Chemically they are typically stable in the pH range of 5 to 10, particularly at an alkaline pH of 8.0 to 9. Generally, they are effective against various types of soil in an aqueous medium having a temperature of about 20C to about C. Naturally, different proteolytic enzymes have different degrees of effectiveness in aiding in the removal of specific stains from textiles and linen.

Instead of, or in addition to, the proteolytic enzyme, an amylase may be present such as a bacterial amylase of the alpha type (e.g., obtained by fermentation of B. subtilis). One very suitable enzyme mixture contains both a bacterial amylase of the alpha type and an alkaline protease, preferably in proportions to supply about 100,000 to 400,000 Novo alpha-amylase units per Anson unit of said alkaline protease.

On a solids basis, i.e., a water-free basis, the enzyme preparation content of the granules or beads can be varied widely and generally will be in the range of 2 to .50 percent by weight of enzyme preparation or 0.1 to 4 percent by weight of active enzyme. When the particulate enzyme preparation has an alkaline protease content of 1.5 Anson units per gram, this range of course represents some 3 to 75 Anson units per grams of granules or beads. The invention finds its greatest utility, however, for the manufacture of granules or beads which are relatively high in enzyme preparation content. containing at least 10 percent by weight of the enzyme preparation (corresponding to say at least 15 Anson units per 100 grams of the granules) and preferably at least 15 percent by weight. In the final washing product, made for example by blending the enzyme containing granules or beads with other granular material (such as spray-dried hollow beads or spongeous low density granules), the content of powdered enzyme preparation is much lower, e.g., in the range of about 0.10 to 4.0 percent, preferably about 0.3 to 2.0 percent.

The amount of the granular enzyme product present in the detergent composition will, of 0.3 to about depend to some extent on the amount of the detergent composition which is to be added to the wash water. For detergent compositions which are intended for use at concentration of, say, about 0.15 percent in the wash water of an automatic home laundry machine, one suitable amount of granular enzyme product is such as to provide 1 Anson unit of alkaline protease for each 100 to 500 (e.g., 200 to 400) grams of the detergent composition. Thus, in a heavy-duty laundry detergent composition, the enzyme-containing granulate composition will form about 0.3 to about 30 percent by weight and the balance will be a mixture of synthetic organic detergent and water-soluble builder salts wherein the ratio of detergent to builder salts is in the range of 1:2 to 1:10 by weight.

Generally, the water-soluble, hydratable builder salts used in the process of this invention provide a pH in the range of 4 to 12, preferably in the range of 7 to l l. The water-soluble hydratable builder salt component may be a single salt, a mixture of hydratable salts, a mixture of a hydratable salt with non-hydratable, water-soluble builder salts, or a portion of a multicomponent detergent granule.

The particles of hydratable builder salt which are mixed with the powdered enzyme generally range in particle size from about 0.044 mm to about 3.36 mm, i.e., corresponds to a range of 6 mesh to +325 mesh (U.S. sieve standard). Since these salts contain more fines than the typical spray dried detergent products which range from about 0.2 mm to 2.0 mm they are more prone to dusting. Therefore, the preferred size range of the hydratable builder salt is 0.2 mm to 2.0 mm, with a preferred density range of 0.2 to 1.0 grams/cc.

Typical examples of hydratable organic builder salts which may be employed alone or in the aforementioned admixtures include the trisodium salt of nitrilotriacetic acid and the di-, triand tetrasodium salts of ethylene-diamine tetracetic acid. Preferred inorganic hydratable builder salts are the alkali metal polyphosphate salts which have the property of inhibiting precipitation of calcium and magnesium material in aqueous solution and of contributing to the heavy-duty performance of the liquid detergent product. They may be considered as derived from orthophosphoric acid or the like by the removal of molecularly-bound water, though any suitable means of manufacture may be employed if desired. Such complex or molecularly dehydrated polyphosphate salts may be used in the form of the normal or completely neutralized salt, e.g., pentapotassium tripolyphosphate, pentasodium tripolyphosphate, and potassium acid tripolyphosphate. The alkali metal salts of tetraphosphoric acid may be used also. The alakali metal polyphosphate salts may be used in either anhydrous form or partially hydrated form.

Other hydratable alkaline builder salts may be employed also, such as the soluble alkali metal borates, sulfates, carbonates, and silicates. Usually, the silicates will be employed in suitable combination with other hydratable builder salts such as the polyphosphates. Suitable silicates are those available in solid form and having an alkali oxide to silicon dioxide ratio within the range of about 1:1 to 1:4, and preferably from about 1:2 to 1:3. Examples are sodium silicates having an Na O to SiO ratio of 122.35, 1:2.5, 113.2, 1:2.0, 1:1.6 and l:l. The most highly preferred builder salt is anhydrous sodium tripolyphosphate.

The hydratable builder salt content of the granulate of the invention can be varied widely, for example, in the range of about 20-98 percent by weight of the granulate on a solids basis, i.e., a water-free basis. Typically, it is present in the range of about 40-90 percent by weight on a solids basis.

The granulate composition is expressed on a solids basis because the amount of water present varies with the identity and the amount of each particular hydratable salt. For example, 0.294 parts by weight of water are required for each part of anhydrous sodium tripolyphosphate if the stable sodium tripolyphosphate hexahydrate is formed; whereas, 1.26 parts by weight of water are required for each part of sodium sulfate if the stable sodium sulfate decahydrate is formed. For this reason the granulate composition comprising enzyme preparation attached to a substantially completely hydrated hydratable salt is specified as containing (a) about 2 to 50 percent by weight of enzyme preparation on a solids basis, (b) about 20 to 98 percent ofa hydratable salt, i.e., anhydrous or partially hydrated hydratable salt, on a solids basis, and (c) water in an amount sufficient to substantially completely hydrate said hydratable salt to produce a hydrate thereof containing about to about percent of the theoretical amount of water in the completely hydrated salt. To the extent that the amount of water exceeds the water in the fully hydrated salt, the water will be free water. From the foregoing it is apparent that, in the absence of other ingredients, the composition of the granulate on a solids basis is identical to the composition of the mixture of enzyme preparation and hydratable salt.

The enzyme-containing granulate produced in accordance with this invention may appear in a wide variety of washing products. For example, the granulate may be incorporated in a laundry presoak product or in a laundry detergent or in a dishwashing product. The granulate may be used as a laundry presoak product or it may be admixed with additional builders and a small amount of organic detergent to form a laundry presoak product. A typical presoak product contains a relatively high concentration of builder salt such as about 30 to 95 percent pentasodium tripolyphosphate (calculated as anhydrous pentasodium tripolyphosphate), about 2 to 10 percent of organic surface active detergent, plus other ingredients such as sodium silicate (which acts as a builder salt and also acts to inhibit corrosion of aluminum surfaces), brightening agents and sodium sulfate. A laundry detergent generally has a lower ratio of builder salt to organic surface active agent (e.g., a ratio in the range of about 1:1 to 10:1 and preferably in the range of 2: l-6:l On the other hand, dishwashing products designed for use in automatic dishwashers are usually more alkaline, containing a very high proportion of alkaline builder salt, such as a mixture of the pentasodium tripolyphosphate and sodium silicate; they contain little, if any, organic surface active detergent, e.g., 0.2 to 3 percent. Usually, automatic dishwashing compositions contain a minor proportion (e.g., 0.5 to 5 percent) of an agent to prevent water-spotting such as a dry watensoluble compound which on contact with water, liberates hypochlorite chlorine (e.g., a heterocyclic dichloroisocyanurate); alternatively, a chlorinated phosphate (such as the well known chlorinated trisodium phosphate) may be used to supply both hypochlorite chlorine and some phos phate.

in formulating the washing products, the watersoluble builder salts usually employed are the phosphates and particularly condensed phosphates (e.g., pyrophosphates or tripolyphosphates), silicates, borates and carbonates (including bicarbonates), as well as organic builders such as salts of nitrilotriacetic acid or ethylene diamine tetraacetic acid. Sodium and potassium salts are preferred. Specific examples are sodium tripolyphosphate, potassium pyrophosphate, sodium hexametaphosphate, sodium carbonate, sodium bicarbonate, sodium sesquicarbonate, sodium tetraborate, sodium silicate, salts (e.g., Na salt) of methylene diphosphonic acid, disodium diglycollate, trisodium nitrilotriacetate, or mixtures of such builders, including mixtures of pentasodium tripolyphosphate and trisodium nitrilotriacetate in a ratio, of these two builders, of 1:10 to 10:1, e.g., l:l.

The organic surface active component of the aforementioned washing products may be an anionic, nonionic or amphoteric surface active compound or a mixture of two or more of the foregoing agents may be used.

The anionic surface active agentsinclude those surface active or detergent compounds which contain an organic hydrophobic group and an anionic solubilizing group in their molecular structure. Typical examples of anionic solubilizing groups are sulfonate, sulfate, carboxylate, phosphonate and phosphate.

Examples of suitable anionic detergents which fall within the scope of the anionic detergent class include the water-soluble salts, e.g., the sodium, ammonium, and alkylolammonium salts, of higher fatty acids or resin acids containing about eight to 24 carbon atoms, preferably to 20 carbon atoms. Suitable fatty acids can be obtained from oils and waxes of animal or vegetable origin, e.g., tallow, grease, coconut oil, tall oil and mixtures thereof. Particularly useful are the sodium and potassium salts of the fatty acid mixtures derived from coconut oil and tallow, e.g., sodium coconut soap and potassium tallow soap.

The anionic class of detergents also includes the water-soluble sulfated and sulfonated synthetic detergents having an alkyl radical of 8 to 26, and preferably about 12 to 22 carbon atoms, in their molecular structure. (The term alkyl includes the alkyl portion of the higher acyl radicals.)

Examples of the sulfonated anionic detergents are the higher alkyl mononuclear aromatic sulfonates such as the higher alkyl benzene sulfonates containing from 10 to 16 carbon atoms in the alkyl group in a straight Qrbranched chain, e.g., the sodium, potassium and ammonium salts of higher alkyl benzene sulfonates, higher alkyl toluene sulfonates, higher alkyl phenol sulfonates, and higher alkyl naphthalene sulfonates. A preferred sulfonate is linear alkyl benzene sulfonate having a high content of 3- (or higher) phenyl isomers and a correspondinglylow content (well below 50 percent of 2- (or lower) phenyl isomers, i.e., wherein the benzene ring is preferably attached in large part at the 3 or higher (e.g., 4,5,6 or 7) position of the alkyl group and the content of isomers in which the benzene ring is at-' tached at the 2 or 1 position is correspondingly low. Particularly preferred materials are set forth in US. Pat. No. 3,320,174.

Other suitable anionic detergents are the olefin sulfonates, including long chain alkene sulfonates, long chain hydroxyalkane sulfonates or mixtures of alkenesulfonates and hydroxylalkane-sulfonates. These olefin sulfonate detergents may be prepared in a known manner by the reaction of 80;, with long chain olefins containing 8 to 25, preferably 12-21, carbon atoms and having the formula RCH=CHR where R is a higher alkyl group of six to 23 carbons and R is an alkyl group of l to 17 carbons or hydrogen to form a mixture of sultones and alkene-sulfonic acids which is then treated to convert the sultones to sulfonates. Other examples of sulfate or sulfonate detergents are paraffin sulfonates containing about 10-20, preferably about -20, carbon atoms, e.g., the primary paraffin sulfonates made by reacting long chain alpha olefins and bisulfites and paraffin sulfonates having the sulfonate groups distrubuted along the paraffin chain as shown in US. Pats. No. 2,503,280; 2,507,088; 3,260,741; 3,372,188 and German Pat. No. 735,096; sodium and potassium sulfates of higher alcohols containing eight to 18 carbon atoms such as sodium lauryl sulfate and sodium tallow alcohol sulfate; sodium and potassium salts of a-sulfofatty acid esters containing about 10 to 20 carbon atoms, e.g., methyl a -sulfomyristate and methyl or -sulfotallowate; ammonium sulfates of monoor diglycerides of higher fatty acids, e.g., stearic monoglyceride monosulfate; sodium and alkylolammonium salts of alkyl polyethenoxy ether sulfates produced by condensing l to 5 moles of ethylene oxide with one mole of higher (Cg-C g) alcohol; sodium higher alkyl glyceryl ether sulfonates; and sodium or potassium alkyl phenol polyethenoxy ether sulfates with about 1 to 6 oxyethylene groups per molecule and in which the alkyl radicals contain about eight to'about 12 carbon atoms.

The suitable anionic detergents include also the acyl sarcosinates (e.g., sodium lauroylsarcosinate), sodium and potassium salts of the reaction product of higher fatty acids containing eight to 18 carbon atoms in the molecule esterified with isethionic acid, and sodium and potassium salts of the higher fatty acid amide of methyl taurine, e.g., sodium cocoyl methyl taurate and sodium stearoyl methyl taurate.

Anionic phosphate surfactants in which the anionic solubilizing group attached to the hydrophobic group is an oxyacid of phosphorous are also useful in the detergent compositions. Suitable phosphate surfactants are the sodium, potassium and ammonium alkyl phosphate esters such as (R-O) PO M and ROPO M in which R represents an alkyl chain containing from about eight to about 20 carbon atoms or an alkyl phenyl group having eight to 20 carbon atoms and M represents a soluble cation. The compounds formed by including about one to 40 moles of ethylene oxide in the foregoing esters, e.g., [R-O-(EtO),.] PO M, are also satisfactory.

The particular anionic detergent salt will be suitably selected depending upon the particular formulation and the proportions therein. Preferred salts include the ammonium, substituted ammonium (mono-, diand triethanolammonium), alkali metal (such as sodium and potassium) and alkaline earth metal (such as calcium and magnesium) salts of the higher alkyl benzene sulfonates, olefin sulfonates, the higher alkyl sulfates, and the higher fatty acid monoglyceride sulfates.

The nonionic synthetic organic detergents are generally the condensation product of an organic aliphatic or alkyl aromatic hydrophobic compound and hydrophilic ethylene oxide groups. Practically any hydrophobic compound having a carboxy, hydroxy, amido, or amino group with a free hydrogen attached to the nitrogen can be condensed with ethylene oxide to form a nonionic detergent. Further, the length of the polyetheneoxy chain can be adjusted to achieve the desired balance between the hydrophobic and hydrophilic elements.

The nonionic detergents include the polyethylene oxide condensate of one mole of alkyl phenol containing from about six to about 12 carbon atoms in a straight or branched chain configuration with about 5 to 30 moles of ethylene oxide, e.g., nonyl phenol condensed with 9 moles of ethylene oxide, dodecyl phenol condensed with 15 moles of ethylene oxide and dinoxyl phenol condensed with 15 moles of ethylene oxide. Codensation products of the corresponding alkyl thiophenols with 6 to 30 moles of ethylene oxide are also suitable.

Also included in the nonionic detergent class are the condensation products of a higher alcohol containing about eight to 22 carbon atoms in a straight or branched chain configuration condensed with about to 30 moles of ethylene oxide, e.g., lauryl-myristyl alco hol condensed with about 16 moles of ethylene oxide.

Another well known class of nonionic detergents is the condensation product of ethylene oxide on a hydrophobic base fonned by the condensation of propylene oxide and propylene glycol. These materials are sold under the trade name Pluronic." The molecular weight of the hydrophobe ranges from about 1,500 to 1,800 and the polyethylene oxide content may comprise up to 50 percent of the total weight of the condensate.

Other nonionic detergents include the ethylene oxide addends of monoesters of hexahydric alcohols and inner ethers thereof with higher fatty acids containing about l0 to carbon atoms, e.g., sorbitan monolaurate, sorbitan mono-oleate, and mannitan monopalmirate.

The amphoteric detergents which can be used in the compositions of this invention are generally watersoluble salts of derivatives of aliphatic amines which contain at least one alkyl group of about eight to 20 carbon atoms and an anionic water solubilizing carboxyl, sulfo or sulfato group in their molecule.

The suitable ampholytic or amphoteric detergents which can be used in the compositions of this invention generally contain a hydrophobic alkyl group of about eight to 18 carbon atoms, at least one anionic watersolubilizing group, e.g., carboxy, sulfo, sulfato, phosphate, or phosphono, and at least one cationic group, e.g., non-quaternary nitrogen, quaternary ammonium, or quaternary phosphonium group, in their molecular structure. The alkyl group may be straight chain or branched and the specific cationic atom may be part of a heterocyclic ring.

Examples of suitable ampholytic detergents include the alkyl betaaminopropionates, RN(H) C H COOM; the alkyl betaiminodipropionates, RN(C l-l, COOM) and the long chain imidazole derivatives having the following formula:

CH1 N \CHI W R i .i

i RaCOOM wherein R is an alkyl group of about eight to 18 carbon atoms, W is selected from the group of R OH, R OM and R OR COOM, Y is selected from the group consisting of OH*, R SO and R OSO R, is an alkylene or hydroxyalkylene group containing one to four carbon atoms, R is selected from the group consisting of alkyl, alkyl aryl and fatty acyl glyceride groups having six to 18 carbon atoms in the alkyl or an acyl group, and M is a water-soluble cation, e.g., alkali metal, ammonium or alkyl-olammonium. Preferred detergents are sodium N-lauryl beta-aminopropionate, disodium N-lauryl iminodipropionate, and the disodium salt of 2-lauryl-cycloimidium-l-hydroxyl, l-ethoxyethanoic acid, l-ethanoic acid. Other imidazole detergents are described in US. Pat. Nos. 2,773,068; 2,781,354 and 2,781,357.

Other suitable amphoteric detergents are the sultaine and betaine types having the following general structure:

wherein R is an alkyl group containing about eight to 18 carbon atoms, R, and R are lower alkyl groups containing one to three carbon atoms, R, is an alkylene or hydroxyalkyiene group containing about one to four carbon atoms, and X is an anion selected from the group consisting of SO (sultaine) and COO"(- betaine). Preferred compounds are l-(myristyl dimethylammonio) acetate and l-(myristyl dimethylammonio)-Z-hydroxypropane-3-sulfonate.

Another class of suitable amphoteric detergents is the amphoteric imidazoline having the following structure:

wherein R is a higher acyclic group of 7 to 17 carbon atoms. The acyclic groups may be derived from coconut oil fatty acids (a mixture of fatty acids containing eight to 18 carbon atoms), lauric fatty acid, and oleic fatty acid and the preferred groups are C, C alkyl groups.

Various other materials may be present in the washing products. Thus, materials such as the higher fatty acid amides may be added to improve detergency and modify the foaming properties in a desirable manner. Examples thereof are the higher fatty acid alkanolamides, preferably having 2-3 carbons in each alkanol group attached to a fatty acyl radical containing 10-18 carbons (preferably 10-14 carbons), such as lauric or myristic monoethanolamides, diethanol-amides and isopropanolamides.

Other suitable foam builders are the tertiary amine oxides of the general formula R R R; N 0 wherein R, is an alkyl radical of about 10 to 18 carbon atoms, R, and R are alkyl or hydroxyalkyl groups containing one to three carbon atoms, and the arrow represents a semipolar bond. lncluded among the satisfactory amine oxides are lauryl dimethyl amine oxide and myristyl dimethyl amine oxide.

Fatty alcohols of 10-18 carbon atoms such as lauryl or coconut fatty alcohols, or cetyl alcohol are suitable additives also. A hydrotropic material such as the lower alkyl aryl sulfonates, e.g., sodium toluene or xylene sulfonates, can assist processing also. In general, these materials and the foregoing foam builders are added in minor amounts, usually from about A to 10 percent, preferably 1 to 6 percent, based on the total solids.

The mixtures may also contain optical brightening agents or fluorescent dyes (e.g., amounts in the range of about one-twentieth percent to one-half percent; I

germicidal ingredients such as halogenated carbanilides, e.g., trichlorocarbanilide, halogenated salicylanilide, e.g., tribromosalicylanilide, halogenated bisphenols, e.g., hexachlorophene, halogenated trifluoromethyldiphenyl urea, zinc salt of l-hydroxy-Z- pyridinethione and the like (e.g., in amounts in the range of about 1/50 to 2 percent; soil-suspending agents such as sodium carboxymethyl cellulose or polyvinyl alcohol, preferably both, or other soluble polymeric materials, such as methyl cellulose (the amount of suspending agent being in the range of about l/20 to 2 percent); antioxidants such as 2,6-di-tert-butylphenol or other phenolic antioxidant materials (e.g., in amounts in the range of about 0.001 to 0.1 percent); coloring agents; bleaching agents; and other additives.

A particularly suitable composition, for use as a granular detergent material contains builder salt such as sodium tripolyphosphate and a mixture of a linear alkylbenzenesulfonate, as previously described, soap and a nonionic detergent, with the soap and nonionic detergent being present in minor proportions. About 50 to 1,000 parts by weight of builder salt are employed per 100 parts by weight of the mixture of linear alkylbenzenesulfonate, soap and nonionic detergent.

v The ratios of the amounts of (A) soap, and (B) nonionic detergent, to (C) the total amount of the synthetic anionic sulfonate detergent in the mixture are preferably as follows: AzC, about 1:10 to 1:2, preferably about 1:4 to 1:6, on an anhydrous basis: B:C about 1:10 to 1:3, e.g., about 1:4 to 1:6, on an anhydrous basis. The component (C) is preferably solely a linear alkylbenzenesulfonate although it may comprise a blend of the linear alkylbenzenesulfonate detergent with other anionic synthetic sulfate or sulfonate detergents (e.g., olefin sulfonates, paraffin sulfonates having the sulfonate groups distributed along the paraffin chain, or alkyl sulfates) with the alkylbenzenesulfonate consistuting, say H3, H2 or 2/3 of this blend.

The following example is given to illustrate this invention further. In this example, as in the rest of the application, all proportions are by weight unless otherwise specified. Also, in this example, the pressure is atmosphe'ric unless otherwise specified.

EXAMPLE 3.6 parts of anhydrous sodium tripolyphosphate are mixed with 0.4 parts of proteolytic subtilisin enzyme preparation (Alcalase) in a powder mixer. The mixture is then blended with 1.0 part of crushed ice in Patterson & Kelly Twin Shell Blender. The crushed air has a particle size range of 0.5 mm to 5.0 mm and the amount of ice particles is sufficient to obtain a hydrate containing 95 percent of the calculated 6 moles of water in the stable tripolyphosphate hexahydrate.

The anhydrous sodium tripolyphosphate particles used have the following screen analysis prior to granulation:

Mesh Opening(mm) Remaining on Mesh 20 0.84 40 0.42 l 60 0.25 l 80 0.177 1 I 0.149 2 200 0.074 61.0 325 0.044 30.0 Pan 0.044 4.0

The temperature of the granulate increases from about 25C. to about 30C. during the 4 minute mixing period. The temperature of granulation mixture at the conclusion of the mixing period is about 28C. The

granulate particles are aged quiescently for five minutes after the mixing is completed. They have a volume density of 0.91 g/cm and the following screen analysis:

Mesh Opening(mm) Remaining on Mesh 12 1.68 3.5 20 0.84 2.6 40 0.42 3.8 60 0.35 11.8 0.177 64.1 100 0.149 7.4 200 0.074 4 Pan 0.074 0.4

If a corresponding amount of water is used in place of the ice particles, the temperature during granulation ranged from about 25C. to about 41C. and only 70.2 percent of the particles remained on a screen having openings of 0.149 mm compared to 93.2 percent when crushed ice is used. Moreover, when water is used, the fines content, i.e., the particles having a size of less than 0.044 mm, is 4.0 percent as compared with somewhat less than 0.4 percent when ice is used.

1 part of the above granules is blended in a twin shell blender with 2.5 parts of sodium perborate and 6.5 parts of a spray dried detergent containing about 40 percent sodium tripolyphosphate about 12 percent soap, about 7 percent ethoxylated polyalkylene glycol nonionic surface active agent (Tergital XD), about 8 percent moisture and about 33 percent sodium sulfate to produce a laundry product.

The laundry product has excellent stability upon aging at room temperature, at 43C., and at 32C. and 99 percent relative humidity. it exhibits high enzyme activity, i.e., shows little thermal degradation of the enzyme component, and is substantially non-dusty.

1n the above example, other anhydrous and partially hydrated builder salts may be substituted for anhydrous sodium tripolyphosphate and the amount of ice adjusted as desired.

it will be apparent to those skilled in the art that variations and modifications of this invention can be made and that equivalents can be substituted therefor.

We claim:

1. A process for producing a granular enzyme product which consists essentially of granulating 0.4 parts by weight of particulate proteolytic subtilisin enzyme preparation having'a particle size of about 0.01-0.15 mm. and 3.6 parts by weight of a particulate anhydrous :sodium tripolyphosphate having a particle size such that about percent are smaller than 0.84 mm. and larger than 0.044 mm. and about 95 percent of the particles are smaller than 0.149 mm., with 1.0 part by weight of ice particles at a temperature between about 25C. and 30C., said ice particles having a particle size of about 0.1 to 10 mm., said anhydrous sodium tripolyphosphate and said particulate enzyme preparation being premixed and then contacted with said ice, to substantially completely hydrate said sodium tripolyphosphate and form granular enzyme product, the particles of which are substantially up to 2 mm. in size with at least 70 percent of the particles being at least 0.177 mm. in size.

2. A process as claimed in claim 1 wherein said particulate enzyme preparation and said particulate hydratable salt are premixed and then contacted with said ice.

3. A process as claimed in claim 1 wherein said particulate enzyme preparation, said particulate hydratalble salt, and said ice are contacted with each other simultaneously.

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2. A process as claimed in claim 1 wherein said particulate enzyme preparation and said particulate hydratable salt are premixed and then contacted with said ice.
 3. A process as claimed in claim 1 wherein said particulate enzyme preparation, said particulate hydratable salt, and said ice are contacted with each other simultaneously. 